This invention relates to the field of balloon dilatation. More particularly, this invention relates to improved balloon dilatation systems wherein dilatation balloons are attached to the distal end of advancement means.
Balloon dilatation catheters have been used to dilate various types of strictures in blood vessels and other body lumens for over twenty years. Typically, such catheters comprise a balloon mounted on the distal end of an elongated flexible shaft and an inflation tube or lumen extending longitudinally within the shaft from its proximal end to the interior of the balloon. Among the major advancements in balloon dilatation catheters has been the development of smaller catheters that can be used in smaller and/or more distal anatomical locations, and the development of catheters that can be rapidly exchanged. Examples of such catheters are described in U.S. Pat. No. 4,748,982 (Horzewski), U.S. Pat. No. 4,762,129 (Bonzel), U.S. Pat. No. 5,040,548 (Yock), U.S. Pat. No. 5,061,273 (Yock), U.S. Pat. No. 5,569,199 (Solar) and U.S. Pat. No. 5,728,067 (Enger). Because these catheters have become more sophisticated and complex in design, and despite the manufacturers"" experience in manufacturing them, these catheters are expensive to make. Furthermore, despite these improvements, difficulties are still encountered in advancing catheters through tortuous anatomy and safely crossing very tight strictures and stenoses in the vascular system and other body lumens or cavities.
Recently vascular stents have been shown to play an important role in reducing the restenosis rates associated with balloon angioplasty. However, stents are sometimes lost from the delivery systems and are difficullt to retrieve safely. In addition, stents cannot completely overcome the trauma and injury that result from balloon dilatation. Thus, there is a need for an enhanced balloon dilatation catheter.
It is an object of the invention to provide an enhanced dilatation system that is extremely low-profile to more easily and safely cross very tight strictures and stenoses in the vascular system and other body lumens or cavities.
It is also an object of the invention to provide an enhanced dilatation system that provides for an improved means for crossing tight stenoses, as well as to navigate tortuous anatomy.
It is another object of the invention to provide an enhanced dilatation system, that has the ability to be exchanged rapidly.
It is yet another object of the invention to provide an enhanced dilatation system that can be used to retrieve dislodged stents.
It is a further object of the invention to provide an enhanced dilatation system that can be manufactured inexpensively and more reliably then currently available stents.
It is a yet further object of the invention to provide an enhanced dilatation system that has means to dilate stenoses while causing less trauma to the patient.
It is also an object of the invention to provide an enhanced dilatation system allows placement of an additional catheter or instrumentality adjacent to said dilatation catheter.
These and other objects of the invention will become more apparent from the discussion below.
According to the invention, an enhanced balloon dilatation system comprises an elongated advancement member which terminates in a tubular tracking member, and an inflatable dilatation balloon having proximal and distal ends. The proximal end of the dilatation balloon is in fluid communication with an inflation channel, and the distal end of the dilatation balloon is attached to the tubular tracking member. During advancement of the catheter, the dilatation balloon and inflation channel are somewhat coextensive with, but unattached to, the advancement member. The tubular tracking member is slidable over a guidewire.